System, components, and methods for detecting moisture

Abstract

To address this and/or other needs, the present inventor devised, among other things, a passive moisture detection probe that can be installed and left in place to continuously indicate whether the moisture-content in the wall-cavity of a building is below or above a desirable level. One exemplary moisture detection assembly includes a moisture-absorbent sensor element and an indicator. The sensor element, which can be placed in contact with the inner surface of a home's exterior sheathing, expands and contracts in response to the moisture content of the sheathing. The indicator, for example a rod, moves in responsive to the expansion and contraction of the sensor element, with its relative position corresponding to the moisture in the exterior sheathing and thus providing an on-going and observable sign of moisture intrusion.

What is claimed is: 
     
       1. A method of detecting a moisture condition in a building wall having wall cavity defined by an exterior sheathing portion and an interior drywall portion opposite the exterior sheathing portion, the method comprising:
 placing a water-absorbent material in contact with an interior surface of the exterior sheathing portion so that the material can absorb water that may infiltrate the exterior sheathing portion; and 
 indicating detection of the moisture condition in response to the water-absorbent material expanding and pushing a portion of an indicator outside the wall cavity from a first position to a second position. 
 
     
     
       2. The method of  claim 1 , wherein the water-absorbent material includes a Hydroxy Terminated Poly (Oxyalkylene) Polyol. 
     
     
       3. The method of  claim 1 , further comprising actuating an electrical switch in response to movement of the indicator to the second position; and wherein movement of the indicator to the second position indicates a moisture condition of at least 20%. 
     
     
       4. The method of  claim 1 , wherein moving at least a portion of an indicator outside the wall cavity from a first portion to second position, includes compressing a spring configured to bias the indicator toward the interior surface. 
     
     
       5. A passive moisture detection assembly comprising:
 an elongated structure configured to extend across a wall cavity defined by an interior surface of a sheathing wall of a building and an interior wall of the building; 
 a material composition configured for expansion or contraction in response to ambient moisture, the material composition positioned at a first end of the elongated structure to contact the interior surface of the sheathing wall and to absorb water that may infiltrate the sheathing wall; and 
 an indicator having a portion positioned at a second end of the elongated structure and configured to be pushed outside the wall cavity and away from the first end of the elongated structure by the material composition in response to moisture-induced expansion of the material composition. 
 
     
     
       6. The assembly of  claim 5 :
 wherein the material composition defines at least a portion of a sensor element; 
 wherein the elongated structure has a length dimension and includes an axial passage generally parallel to the length dimension; and 
 wherein the indicator comprises a rod portion and a cap portion, with the rod portion extending through the axial passage and having a first end contacting the sensor element and a second end connected to the cap portion, with the cap portion having a portion configured for placement outside the wall cavity. 
 
     
     
       7. The assembly of  claim 5 , wherein the material composition consists essentially of a Hydroxy Terminated Poly (Oxyalkylene) Polyol. 
     
     
       8. The assembly of  claim 5 , wherein the material composition comprises a reaction product of a polyether with toluene diisocyanate. 
     
     
       9. The assembly of  claim 5 :
 wherein the material composition defines at least a portion of a sensor element; 
 wherein the elongated structure defines a chamber having first and second end portions and an intermediate portion extending between the first and second end portions, with the first end portion at least partially containing the sensor element and the indicator including a rod extending through the intermediate portion and at least partially into the second end portion. 
 
     
     
       10. The assembly of  claim 9 :
 wherein the rod has an end rod portion at least partially within the second end portion of the chamber; and 
 wherein the assembly further includes an end cap having a head portion at least partially outside the wall cavity and a stem portion extending from the head portion into the second end portion of the chamber to connect with the end rod portion. 
 
     
     
       11. The assembly of  claim 10 :
 wherein the second end portion of the chamber extends at least partially through the interior wall; and 
 wherein the assembly further includes means, coupled to the second end of the chamber, for keeping the chamber substantially perpendicular to the interior surface of the sheathing wall. 
 
     
     
       12. The assembly of  claim 11 , wherein the means for keeping the chamber substantially perpendicular to the interior surface of the sheathing wall includes a plate having an opening and two or more prongs extending perpendicularly from the plate through a hole in the interior wall into the wall cavity. 
     
     
       13. A moisture detection assembly for at least partial placement within a wall cavity of a building, the wall cavity defined by an exterior sheathing wall and an interior wall, the assembly comprising:
 housing means for extending across the wall cavity and holding a water-absorbent material in contact with an interior surface of the exterior sheathing wall; and 
 means, at least partially within the housing means and responsive to expansion of the water-absorbent material, for pushing an indicator outside the wall cavity to indicate a moisture condition within the sheathing wail. 
 
     
     
       14. The moisture detection assembly of  claim 13 , wherein the water-absorbent material consists essentially of a reaction product of a polyether with toluene diisocyanate. 
     
     
       15. The moisture detection assembly of  claim 13 :
 wherein the water-absorbent material at least partially defines a sensor element; 
 wherein the means for moving at least a portion of an indicator includes a rod having a first end coupled to the sensor element and a second end coupled to an end cap that is at least partially outside the wall cavity and adjacent to the interior wall; and 
 wherein the means for extending across the wall cavity includes a tubular housing enclosing a least a portion of the rod and a portion of the sensor element. 
 
     
     
       16. The moisture detection assembly of  claim 15 , further comprising a spring element within the housing for biasing the sensor element into contact with the sheathing wall. 
     
     
       17. The moisture detection assembly of  claim 13 , wherein the assembly further comprises means, coupled to the means for extending across the wall cavity, for keeping the means for extending substantially perpendicular to the interior surface. 
     
     
       18. The moisture detection assembly of  claim 17 , wherein the means for keeping the housing means substantially perpendicular includes a plate having an opening and two or more prongs extending perpendicularly from the plate through a hole in the interior wall into the wall cavity. 
     
     
       19. The moisture detection assembly of  claim 18 , wherein second end portion of the chamber extends through the opening in the plate to engage with and cause the two or more prongs to spread open against sides of the hole in the interior wall.